Title: Nowcasting and Short-term Forecasting of Thunderstorms and Severe Weather Using OSCER
1Nowcasting and Short-term Forecasting of
Thunderstorms and Severe Weather Using OSCER
- Keith A. Brewster1Jerry Brotzge1, Kevin W.
Thomas1, Jidong Gao1, Ming Xue1,2 and Yunheng
Wang1 1Center for Analysis and Prediction of
Storms - 2School of MeteorologyUniversity of Oklahoma
Oklahoma Supercomputing SymposiumOctober 12, 2011
2CASA NEXRAD Radars
- CASA NetRadNSF ERC Collaborative Adaptive
Sensing of the Atmosphere - X-Band Dual-Pol Radars
- 40 km nominal range
- Collaborative, Adaptive Scanning
- Fill-in below coverage of NEXRAD
- Toward phased-array panels low-cost!
- NEXRAD
- S-Band Radars
- 14 covering domain
- Data used out to 230 km
3CASA NetRad Network
Southwest Oklahoma
4Spring 2007-2009 Near-Real TimeForecast Domain
Dx 1 km 53 Levels 600x540
Radars Used 4 CASA 14 NEXRAD
PlusSatellite Surface Data
540 km
600 km
5CASA Forecasting Workflow
Observations
CAPS Ingest Cluster Linux ServerObservation
Pre-Processing
Mesonet Sfc Obs Processing
Radar Data File Selection
Input File Generation
Operational Forecast Model Data
CAPS Ingest Cluster
OSCER Sooner SupercomputerAnalysis Data
Assimilation
Graphics on WW Web
Radar Data QC and Remapping
ARPSForecastModel
3DVAR Analysis
Model Interpolation
CYCLE
OSCER Sooner SupercomputerRun Forecast Model
PSC Mass Store CAPS Linux Cluster3D Data File
Archive
ARPSForecast Model
GraphicsGeneration
6Improving the MPI Efficiency of Radar Remapper
Radar data are converted from 3-D polar to 3-D
Cartesian coordinates.
Original StrategyHorizontal Domain
Decomposition
Each processor finds solution on columns within
its domain
nproc_y5
nproc_x5
Potentially uneven workload
7Improving the MPI Efficiency of Radar Remapper
Radar data are converted from polar to Cartesian
coordinates of model grid.
- Improved Algorithm
- For each radar
- Within domain decomposition, determine columns
having valid data - Collect columns with valid data in 1-D array
- Distribute work for these columns uniformly among
processors - Execute remapping algorithm MPI
- Distribute results to original home processor for
output.
nproc_y5
nproc_x5
8Real-Time NWP Runs 2009
- Run on Parallel Linux Boxes OU
OSCER 600 processors/2 runs at a time - Total Run Time 1.5 hours
- Two Runs in Near Real-time
- 9 Weeks in Spring Season
- 6-hour 1-km resolution forecasts
- Use Radar Reflectivity Radial Velocity
- 3DVAR wind with ADAS cloud analysis
- ARPS Model
- Runs posted to Web in real-timehttp//www.caps.ou
.edu/wx/casa/
CASA NEXRAD No CASA Data
92007-2009 Assimilation Strategy
40-min Assimilation
5.5-hour Forecast
IAU
IAU
IAU
IAU
0210
0220
0230
07
0200
03
04
05
06
0150
08
Manual on-demand model start-up for storms in the
network.
10Assimilation vs. Analysis Wind Speed/Vectors
500m AGL 0220 UTC
Chickasha Radar
11Temperature
Forecast temperature perturbation Vort. at z
500m AGL
End of Data Assimilation Period
0220 UTC 0230 UTC
Movie
0240 UTC 0250 UTC
12Impact of CASA Data
NEXRAD Only
CASA NEXRAD
1-minute output CASA NEXRAD vs NEXRAD-Only
132010 Nowcast Strategy
Domain size 350 x 320 x 53. Total Run Time lt 10
min 800 cores (100 dual-quad-core
servers) Forecast model run every 10-min
whenever the radars were operating (during
precipitation).
14Sample 10 May 2010 2140
From NWS Norman
152140 UTC Nowcast/Forecast
T05 min (assimilated state) 2140
162140 UTC Nowcast/Forecast
T15 min 2150
172140 UTC Nowcast/Forecast
T25 min 2200
182140 UTC Nowcast/Forecast
T35 min 2210
192140 UTC Nowcast/Forecast
T45 min 2220
202140 UTC Nowcast/Forecast
T55 min 2230
21Data AssimilationAccomplishments
- Developed a very efficient real-time data
assimilation, nowcasting and forecasting system - Demonstrated initial impacts of CASA data on
cloud-scale analysis and forecasting - Advanced real-time storm-scale assimilation to
where we can directly compare forecasted
small-scale vorticity features to radar
signatures - Major step towards warn on forecast
22Ongoing Work Using CASA Data
- Objective Verification of recent forecasts, to
also include object-based methods. - Rainfall (using QPE field from NSSL)
- Vorticity Centers
- Methods to improve data assimilation
- Improvements to current algorithms
- More sophisticated, but expensive, algorithms
Acknowledgments NSF Sponsors CASA ERC Computing
OU OSCER
23In 2012 moving the radars to the Dallas/Ft Worth
Metro
24More radars will be added during the year.